Roadside bordering weedy fallow field, in full sun. The Grindelia was dominant in a band close to the road. With Polygonum cf aviculare, Rumex patentia, Dipsacus, etc.
Description
Abundant on Grindelia squarrosa; the Grindelia was abundant along the road side for 200m or so and the plants were consistently highly infected.
Voucher image
Photos posted on iNaturalist: https://www.inaturalist.org/observations/240389312.